Method of treating hydrocephalus

ABSTRACT

This disclosure relates to a catheter and method for its use to establish a connection between the cerebral ventricles and the proximal segment of a ligated neck vein for treating hydrocephalus. This method for shunting the cerebrospinal fluid (CSF) to the venous circulation prevents blood from coming into contact with the shunt tube and prevents a syphonage force from developing when the patient assumes the upright position. The catheter consists of a tubing of soft tissue-compatible material and is provided with a simple check valve to prevent reflux of blood. It has a side tube and it is also provided with means for: 1) easy insertion into the ventricle; 2) protection of the intake apertures; 3) watertight closure of the dura mater around it; 4) resistance to kinking; 5) provision of an available extra length of 5 cms; and 6) resistance to being pulled out of the neck vein due to movements of the head and neck.

United States Patent El-Shafei 1 July 15, 1975 METHOD OF TREATINGI'IYDROCEPHALUS [5 7] ABSTRACT [76] Inventor: Ismail Lotly El-Sh f i, 9(Ah d This disclosure relates to a catheter and method for its Heshmatstr zamalik c i Egy use to establish a connection between the cerebralventricles and the proximal segment of a ligated neck [22] Filed veinfor treating hydrocephalus. This method for Appl. No; 446,420

Primary ExaminerDalton L. Truluck Attorney. Agenl. ur FirmWigman & Cohenshunting the cerebrospinai fluid (CSF) to the venous circulationprevents blood from coming into contact with the shunt tube and preventsa syphonage force from developing when the patient assumes the uprightposition. The catheter consists of a tubing of soft tissue-compatiblematerial and is provided with a simple check valve to prevent reflux ofblood. it has a side tube and it is also provided with means for: l)easy insertion into the ventricle; 2) protection of the intakeapertures; 3) watertight closure of the dura mater around it; 4)resistance to kinking; 5) provision of an available extra length of 5cms; and 6) resistance to being pulled out of the neck vein due tomovements of the head and neck.

I Claim, 3 Drawing Figures METHOD OF TREATING HYDROCEPHALUS Thisinvention relates generally to the surgical arts. and more particularlyto a method and apparatus for treating hydrocephalus by establishing aventricle venous shunt between the lateral ventricle and the proximalportion of a ligated neck vein.

BACKGROUND OF lNVENTlON At the present time. there are several valvesystems to provide vcntriculo atrial shunts to drain CSF from theventricles of the brain into the venous blood stream. Examples of thesesystems are: U.S. Pat. No 2.969.066 (Holter et al.); U.S. Pat. No.3.020.913 (Hyer-Pudcnz); and U.S. Pat. No. 3 288.l42 (Hakim).

In treating hydrocephalus using one of these valve systems a catheter isthrust into the ventricles of the brain in order to drain unwanted fluidtherefrom. and is then led through the jugular vein into the heart sothat the fluid from the ventricles enters the blood stream and isdisposed of by the process of purification of the blood.

Two main disadvantages encountered with conven' tional shunt systemsare:

l. the development of a syphonage force whenever the patient assumes theupright position. This force corresponds to the height of the CSF columnin the shunting catheter and eventually causes excessive ventriculardrainage which may lead to the development of intracranial hacmorrhageand/or collapse of the cerebral ventricles increasing the chances ofblockage of the ventricular end of the shunting catheter;

2. the shunting catheter which lies directly in the blood stream acts asa foreign body and may excite blood clotting, venous thrombosis andembolic complications.

Therefore. as disclosed in co-pending application Ser. No. 316,995. thepurpose of the shunt system and the catheter of this invention is ingeneral to avoid all the above difficulties and complications byproviding means for treating hydrocephalus by using the catheter of thisinvention to establish a connection between the cerebral ventricles andthe proximal segment of a li gated neck vein, e.g., the external jugularvein (EJV) or the common facial vein (CFV).

In the aforementioned co-pending application Ser. No. 3 I 6,995 it isdisclosed that the reason for the reflux of blood into the venous end ofa non-valved shunting tube is the fact that there is a reduction in thesuction effect exerted on the CSF caused by the running blood in theveins during periods of high intrathoracic pressure, as compared withthe suction effect during periods of normal intrathoraeic pressure.Accordingly. a catheter and method for its use was disclosed which couldbe inserted into the vein in such a way as to prevent the suction effectof the running blood from exert ing its effect on the CSF so that theblood would not regurgitate into the tube during periods of highintrathoracic pressure. This method of establishing the ventri clevenous connection commprised inserting the ventricle end of the catheterinto the lateral ventricle such that no CSF could leak from the duralhole made for the tube insertion into the ventricle, and the open venousend of the tube was to be inserted into the proximal segment ofa ligatedneck vein against the direction of blood flow. The catheter disclosed inthe instant application represents an improvement over the catheter asdisclosed in the aforementioned co-pending application. Moreover. theinstant application includes further details and elaboration of themethod disclosed in the aforementioned co-pending application.

Accordingly. it is a primary object of this invention to provide amethod for establishing a ventriculo venous (VV) connection to theproximal segment ofa ligated neck vein which will avoid most ofthedifficulties and complications encountered in treating hydrocephalus bythe conventional ventriculo-atrial drainage systems More particularly.it is an object of this invention to provide a catheter which willfacilitate establishing the aforementioned \v'V connection.

Another object of this invention is to provide a cathcter made oftissue-compatible material having means for easy insertion into thecerebral ventricle through a small dural hole.

Another object of this invention is to provide a catheter asabovedescribed having means for protection of the drainage apertures inthe wall of the catheter tubing at its ventricular end.

Still another object of this invention is to provide a catheter havingmeans which will facilitate a watertight closure of the dura materaround the catheter.

Yet another object of this invention is to provide a catheter as abovedescribed having means for introducing a stylet therein to provide anaxial force for inserting the catheter into the ventricle.

A further object of this invention is to provide a catheter asabove-described having means for recording pressures in the ventriclesand in the venous side of the \"V connection.

Still another object of this invention is to provide a catheter asabove-described having means for monitoring the patency ofthe shuntsystem provided by the connection.

Another object of this invention is to provide a catheter asabovedescribed having means for prevention of reflux of blood therein.

Another object of this invention is to provide a catheter asabove-described having the provision of an available extra 5 ems to thelength of the catheter which will accommodate variations in the lengthof body segment bridged by the catheter.

A further object of this invention is to provide a catheter asabove-described having resistance to kinking at the sites of curves inthe course of the catheter as well as resistance to being pulled out ofthe vein due to movements of the head and neck.

With the above and other objects in view that may hereinafter becomeapparent. the nature of the invention may be more clearly understood byreference to the several views illustrated in the accompanying drawings.the following detailed description thereof. and the appended claimedsubject matter:

IN THE DRAWINGS FIG. I is a schematic illustration of the head and neckof an individual. and illustrates the ventriculo venous sbunt (VV) ofthis invention showing the catheter in its place to establish theconnection between the cerebral ventricle and the proximal segment of aligated EJV;

FIG. 2 is a plan view of the catheter of this invention, having portionsthereof cut away for clarity to illustrate internal portions thereof;

Referring now to the drawings in detail. there is illustrated in FIG. 2a catheter made of soft silicone rubber or any other tissue-compatiblematerial and has a simple. unidirectional check valve (V) incorporatednear its middle. For purposes of description. the catheter can bedivided into a ventricular segment and a venous segment between whichthe check valve (V) is incorporated. The ventricular segment extendsfrom the ventricular tip to the check valve and comprises the following:l) a ventricular tip (A) which is firm blind pointed with a depression(D) on its inside for lodging a stylet (S). FIG. 3. which is used toprovide an axial force for inserting the catheter into the ventricle.This arrangement keeps the pointed tip pointing forwards and permits itseasy insertion through a tiny dural hole; (2) intake apertures (H) inthe wall of the first two centimeters of the ventricular end of thecatheter which permit the flow oI'CSF from the ventricle into thecatheter; (3) soft silicone rubber flanges (Fl) attached to the catheterwall and projecting between the apertures (H) protect them by bendingand closing them during insertion of the catheter into the ventricle andreopen inside the ventricle thereby keeping the apertures away from thewall of the ventricle and from the choroid plexus; (4) a single softsilicone rubber flange (F2) is attached to the catheter at a distanceapproximately 10 ems from the ventricular tip. The flange (F2) marks theextent of catheter to be inserted through the dural hole and is alsoused for obtaining a watertight closure of the dura mater around thecatheter either by using Histacryl to stick the flange to the dura materor by suturing it. This flange (F2) can be made of a larger diameterthan the flanges (Fl protecting the apertures (H); (5) a few centimetersbeyond the flange (F2) 21 side tube (T) projects from the main catheterat an angle of about 45. The side tube is of the same thickness and boreas the rest of the catheter and measures about 4 cms in length. It isused as a means for inserting the stylet (S FIG. 3, into the ventricularsegment of the catheter. It can also be connected to a manometer torecord the pressure in the ventricle or in the vein side of theconnection during the operation. The side tube (T) is tied after thesatisfactory establishment of the VV connection and can be used later tocheck the patency of the shunt system if such a step is ever needed; (6)two strong side flanges (F3) with holes are attached to the catheter atthe point of its junction with the side tube. The flanges (F3) are usedfor fixing the catheter to the periosteum by sutures (FIG. 1, Lig. 3).

The simple check valve (V) which separates the ventricular from thevenous segment of the catheter lies a few centimeters beyond the sidetube (T) This valve prevents reflux of blood into the catheter but ithas nothing to do with the regulation of the intraventricular pressure(IVP).

The venous segment of the tube extends from the check valve till thevenous end and consists of: (l the venous end of the catheter whichincludes a bulbous portion (G) so as to prevent its slipping out fromthe neck vein due to movements of the neck. The outside diameter of thebulbous venous end (G) of the catheter is approximately double that ofthe main portion of the catheter and therefore it is unlikely to slipout from the vein when a ligature is tied around the vein to hold thetube inside it; (2) a kink-proof segment which extends from the bulbousvenous end for a distance of about 15 cms. A spiral wire (Sp.W) isincorporated into the venous portion of the catheter to prevent kinkingand occlusion of the catheter at the point where it curves up to enterinto the tied neck vein; (3) the other half ofthe venous segment has anexpansible telescoping segment (TS) which can provide an extension ofthe tube an extra length of about 5 cms. Such a length is needed toallow for variations in the length of body segment bridged by theshunting catheter as occurs during movements of the head or due to anincrease in length of the individual.

Exemplary dimensions of the elements of this invention may be asfollows: Its length may be approximately 37 ems, the outside diameter ofthe tubing may be approximately 2.2 mms, the lumen may be approximately1 mm. The distance between the ventricular tip and the flange (F2 inFIG. 2) may be approximately IO cms. from the flange (F2) to the sidetube (T) may be ap proximately 3 cms and from the side tube to the valve(V) may be approximately 3 ems. The segment of tube between the checkvalve (V) and the bulbous venous end (G) of the catheter may beapproximately 20 cms. A spiral wire (Sp.W) or any anti-kinking system isincorporated in the 15 cms of tubing next to the bulbous venous end (G)while in the remaining 10 cms of tubing between the end of the spiralwire and the check valve the telescoping segment (TS) is incorporatedinto the catheter. Of course. depending on the intended use and the ageof the patient, these dimensions and arrangements can be varied at will.

The theoretical basis for the suggested ventriculo venous (VV)connection (FIG. 1) is as follows: If a neck vein. cg. the EJV. is tied(Lig. l in FIG. 1) above the valve in its lower end, the pressure in theproximal segment of the vein rises to about +8 to 9 cms saline. If thecatheter of this invention (FIG. 2) is used to establish a connectionbetween the cerebral ventricle and the proximal segment of the ligatedEJV provided that CSF loss or leakage is not allowed to occur, a closedsystem will be established one side of which will be the cerebralventricles and the other side will be the vein segment BC in FIG. 1.Since the pressure in the hydrocephalic ventricles is much higher thanthe pressure in the vein segment BC. the CSF will flow from the cerebralventricle. through the shunt tube and through the vein segment BC,washing the blood away from it and converting it into an extension tothe shunt tube. The CSF enters the venous circulation at point C via thetributaries of the tied vein. The flow of CSF continues until a state ofequilibrium between the pressures in the cerebral ventricles and in thevein segment BC takes place, and the CSF will flow thereafter into thevenous circulation at a rate corresponding to the rate of its formation.

Establishing the VV connection in this way fulfills the followingadvantages: (I the vein segment BC will be converted into an extensionto the shunt tube connecting the venous end of the catheter (at point B)to the circulating venous blood at point C. This vein segment will befull of CSF which acts as a barrier preventing contact between thecatheter and the circulating blood; (2) the higher pressure created inthe proximal segment of the tied vein provides a resistance to the flowof CSF and maintains the intraventricular pressure (IVP) at a levelhigher than the pressure in the vein segment by an amount that willdepend on the rate of CSF formation. The average lVP after establishingthe connection is around +12 ems saline which is within normal limits.This means that no excessive ventricular decompression takes place; (3)reflux of blood into the catheter cannot occur because of a simple checkvalve (V in FIGS. 1 and 2) incorporated into it. Dissimilar from othervalves used in conventional ventriculo-atrial catheters. the valve inthis invention has nothing to do with the regulation of the WP. its onlyjob is to prevent reflux of blood; (4) a syphonage effect does not occurwhen the patient assumes the upright position because of the hydrostaticpressure of the blood in the veins of the head and neck.

METHODS OF ESTABLlSHlNG THE VV CONNECTION The ventricular end of thecatheter is inserted into the cerebral ventricle via a small hole in thedura mater which is exposed through a posterior temporal burr hole. Thesty'let (S). which is approximately ems long wire of a thickness lessthan the bore of the catheter (approximately 0.5mm is introduced via theside tube and passed into the ventricular segment of the catheter tolodge in the depression (D) on the inside of the ventricular tip (A).and is used to provide an axial force to insert the catheter into theventricle until the soft silicone flange (F2 in FIG. 2) Comes intocontact with the dura mater. The flange (F2) is fixed to the dura materusing Histacryl or sutures (Lig. 3) so as to obtain a watertight closureof dura mater around the catheter. The side flanges (F3) at the junctionof the side tube with the main catheter are fixed to the periosteum bysutures. The venous end of the tube is passed through a tunnel under theskin just posterior to the mastoid process and emerges in a neck woundmade to expose the EJV or the CFV. The vein chosen for the anastomosisis tied (if the EJV is used it is tied above the valve in its lower end,ifthe EJV is slender the CFV can be used and it is tied at its entranceinto the internal jugular vein). A side opening is made into the veinwall proximal to the tied ligature and the bulbous venous end (G) of thecatheter is inserted into the vein in an upward direction for a distanceof about 1 cm (FIG. 1) against the direction of the blood stream. Theside opening (SL) in the vein wall is closed around the catheter usingvascular sutures and a ligature (Lig. 4) is tied around the veinproximal to the bulbous venous end ((3) of the catheter to prevent itslipping out of the vein. As a further measure against pulling of thecatheter out of the vein during movements of the neck. a stitch (Lig. 5)is taken to anchor the catheter to the deep l'acia near the veinopening. The force ot'any pull on the catheter will be expended at theanchoring stitch (Lig. 5) and will not be effective at the catheter veinjunction. Throughout the procedure clamps are applied on the side tubeand on the venous segment ofthe catheter to prevent CSF loss. Al'terestablishing the connection. the side tube can be connected to amanometer so as to record the pressure in the cerebral ventricle or inthe vein. The side tube is closed (Lig. 2) and fixed to the periosteumbefore closing the skin wounds.

While the invention has been specifically illustrated and describedherein with reference to a preferred embodiment thereof. it iscontemplated that minor modifications could be made therein withoutdeparting from the spirit of the invention.

1 claim:

1. A method of treating hydrocephalus comprising the steps ofestablishing a connection between the lateral ventricle and a ligatedneck vein using a catheter having a ventricular end and a venous end.eliminating the syphonage force which develops with conventional valvesystems when the patient assumes the upright position. and preventingcontact between the shunting catheter and the circulating blood byinserting the venous end of the catheter into the proximal segment ofthe ligated neck vein against the direction of blood flow.

1. A method of treating hydrocephalus comprising the steps ofestablishing a connection between the lateral ventricle and a ligatedneck vein using a catheter having a ventricular end and a venous end,eliminating the syphonage force which develops with conventional valvesystems when the patient assumes the upright position, and preventingcontact between the shunting catheter and the circulating blood byinserting the venous end of the catheter into the proximal segment ofthe ligated neck vein against the direction of blood flow.